Compatibility brief
Can Oscar live with Otocinclus?
Risky. This mix is commonly discouraged for typical setups.
Compatibility score
Profile confidence: low
How we decideFishori checks adult size and predation risk, behaviour, water requirements and tank needs before giving a verdict.
300L
Combined minimum footprint reference for these two species: about 300L (larger active fish often want more length).
Oscar (about 35cm as an adult) can realistically eat Otocinclus (about 5cm) once grown. Plan around adult sizes, not shop sizes.
Oscar (aggressive) and Otocinclus (peaceful) are far apart on aggression — bullying or injury is a common outcome in average community layouts.
Assessment details
Aggression mismatch
Top issueOscar is aggressive, while Otocinclus is peaceful. The aggressive fish will likely bully or harm the peaceful one.
Oscar may eat Otocinclus
Oscar (35cm) is predatory and Otocinclus (5cm) is small enough to be eaten. This pairing is unsafe.
Compatible temperature range
Both fish can comfortably share similar water temperatures.
“Oscar is aggressive, while Otocinclus is peaceful”
Aggression mismatch
Next steps
Concrete changes, not "research more" filler.
- •Otocinclus should be kept in a group of at least 6 for best health and behaviour.
- •Oscar reaches ~35cm: tank length and turning room matter more than the litre number. A tall, short tank of the same volume is not equivalent.
Try instead
- →Build a species-only tank for the larger fish, or restock with fish too large to be eaten at adult sizes.
- Seriously Fish. Astronotus ocellatus
Primary: aquarium size, water chemistry, behaviour, and compatibility (URL verified in upgrade script; recheck if site content changes).
- FishBase. Astronotus ocellatus
Secondary: taxonomy, distribution, and maximum length in nature; cross-check with aquarium import lines and measured tank parameters.
- Wikipedia. Astronotus ocellatus
Secondary: general species context; verify all husbandry numbers against a dedicated aquarium care sheet and your test kit, not a single table row.
- Wikipedia. Astronotus ocellatus (oscar)
Encyclopaedia overview; use specialist aquarium sources for your stock's real temperature/pH/footprint needs.
- Seriously Fish. Otocinclus macrospilus (Otocinclus ‘affinis’ / trade oto stand-in)
Primary stand-in: SF profile for O. macrospilus. Shop 'O. affinis'/'otocinclus' labels are often misidentified. Verify the fish against a good key, not a single import sticker.
- FishBase. Otocinclus affinis
Secondary: taxonomy, distribution, and maximum length in nature; cross-check with aquarium import lines and measured tank parameters.
- Wikipedia. Otocinclus affinis
Secondary: general species context; verify all husbandry numbers against a dedicated aquarium care sheet and your test kit, not a single table row.
- FishBase. Otocinclus vittatus
Taxonomy, distribution, and typical max length in natural/wild contexts (cross-check to aquarium import lines).
- Wikipedia. Otocinclus
Encyclopaedia overview; use specialist aquarium sources for your stock's real temperature/pH/footprint needs.
Try this next
Build the full stocking list with Oscar + Otocinclus
Plan further
Check each species’ mates list, size the glass, then verify the full stock in the builder. Methodology explains how verdicts are produced.
Individual fish vary in personality. Fishori uses conservative hobby rules. Observe any new introduction closely, feed thoughtfully, and keep a quarantine or backup plan. This is not veterinary advice.
Profile data confidence: high. Checked against several solid care sources that mostly agree. At least one species here has common trade-name ambiguity.